It's one more part of our commitment to America. We're back now with our "Closer look" at the maverick senator shaking up the gop, Rand Paul is running hard. Going places republicans haven't gone before. Even leading the presidential field can he broaden his appeal the way his father never did. ABC's Jon Karl joined him on the trail. Reporter: In Manchester, new Hampshire, this weekend, the freedom summit, a gathering of conservative leaders, including many positioning themselves to run for president in 2016, where we caught up with Kentucky pizza place. So, you have won the last couple of straw polls. A poll nationally, CNN poll has you as a leader. Are you the front-runner now as the nomination? I don't know if it's that good luck or bad luck. It's better than not being noticed. Also, no matter what happens, I think the republican party needs to evolve, change, grow, if we're going to win again, so I do want to be a part of that. Great to be here, Berkeley. Thank you. Reporter: You have been out to Berkeley, Howard university, Detroit, you have been going after audiences that we don't see republicans go after, minorities, young people, they voted overwhelmingly for Barack Obama, what is your party doing wrong to alienate so many young voters, minorities? It's a harden resistance. It's not going to be easy to change. We have 3% of the vote in Detroit. Not one democrat that's offered to help the people in Detroit, I went to the people in Detroit and I offered them a billion dollars of their own money to try to help them recover. Reporter: You offered tax cuts. If you're poverty, tax cuts -- That will be left in the hands of businesses that people in Detroit are already voting on. Let's grow those businesses. Sfwlr I'm sure you saw Jeb bush's comments on immigration. They broke the law but it's not a felony. It's an act of love. Reporter: Do you agree with him on this? You know, I think he made might have been artful in the way he presented this. If it were me, what I would have said is, those who seek the American dream aren't bad people. However, we can't invite the whole world. When you say they're doing an act of love and you don't follow it up but we have to control the border, people think, well, because they're doing this for kind reasons, the whole world can come to our country. Reporter: There's also suggestions that republicans in previous campaigns have vilified those who have come over illegally? And some people have perceived it. Reporter: I want to turn to foreign policy. You were very critical of dick Cheney. You suggested that he was opposed to going into Baghdad in 1991. Dick Cheney then goes to work for Halliburton. Makes hundreds of millions dollars as their CEO. Reporter: Do you think Cheney was motivated by his financial ties with Halliburton? I'm not questioning his motivation. I think he loves his country. Reporter: You said we don't want our defense to be defined by people who make money off the weapons, are you suggesting that's why we went to war in Iraq? No, no. I'm not questioning dick Cheney's motivates. At one point in time, he was opposed to going into Baghdad. He was out of office. Involved in the defense industry. Then he became for going into Baghdad. Reporter: Now, more broadly on foreign policy. Lynn Cheney said, Rand Paul seems to get his foreign policy talking points from Rachel Maddow. That's funny. My talking points would come from Rachel Maddow. Rachel Maddow isn't my biggest champion. Reporter: You look at drones, NSA surveillance. You voted against the Ukraine bill. You're one of two senators against the resolution on Iran and nuclear weapons, on these issues you're more closely associated with the left -- I think that's an incorrect conclusion. I would say my foreign policy is what came out of Ronald Reagan. But Reagan came out of a huge defense buildup. You proposed nearly $50 billion cut to the Pentagon, bigger than the sequester. In proposed increases in spending. I haven't really had a dip down in spending. Sequester actually didn't cut spending. The point is, you proposed curbing defense spending than the sequester. It's not a blank check. Some conservatives I'll give them whatever they want and everything is for their soldiers, they play up this patriotism, we don't have to control defense spending. We can't be in the hole every year. Reporter: In 2012, there was a resolution that the united States should do everything possible to keep Iran from getting a nuclear weapon. Why did -- I repeatedly voted for sanctions against Iran. I think all options should be on the table to prevent them from having nuclear weapons. The way they wrote the resolution -- I don't want to declare war without people actually thinking through this. They said containment would never, ever be our intention. We woke up one day and Pakistan had nuclear weapons. If that would have been a policy toward Pakistan we would be at war with Pakistan. We woke up one day and China had nuclear weapons. People who say, by golly, we'll never stand for that, they're voting for war. Reporter: So, do you think the United States could live with a nuclear-armed Iran? I think it's a mistake for them to get nuclear weapons. Reporter: If they crossed the threshold is it something that we could live with? I think that's not a good idea to announce that in advance. No, that's a dumb idea to say you're going to live with. However the opposite isn't good. Reporter: The final decision on running will be a family one. My wife, Kelly, I couldn't have done it without her. Reporter: Have you convinced your wife to run? You said it would depend on her. There are two votes and at least one undecided. Reporter: When are you going to make the decision? After 2014 elections. Thank you. Thanks to Jon Karl for that. Let's bring in our political roundtable.

This transcript has been automatically generated and may not be 100% accurate.